This is a longitudinal study of the differences in levels of synchrony in early interaction between preterm and term infant- mother dyads and the relationship between levels of synchrony and later developmental deficits. Early interaction between preterms and their mothers are known to be distinctly different and less synchronous. Some researchers found differences linked to poorer cognitive and social outcomes, others found no outcome differences and suggest that interactional differences are adaptive. Contradictory evidence may be due to lack of a consistent operational definition of dyadic synchrony and a practical instrument to measure it. In this study a new instrument, the Dyadic mini Code, is used to measure synchrony in interaction in preterm and term dyads at 3 months of age, and levels of synchrony are related to: 1. Social outcomes of the child at 1 year measured by the Minnesota Child Development Inventory (social competence subscales) and 2. Cognitive outcomes measured at age 2 by Bayley Scale of Infant Development and Memory for Location Tests, and at age 3 by Stanford-Binet. Fifty healthy preterm and 50 term dyads will be home-visited at 3 months, 1, 2 and 3 years of age for data collection, (preterms corrected for gestational age). T-Test analysis will be applied to detect differences in synchrony between (term/preterm) groups. Correlational and multiple regression analysis will identify associations within and across groups between synchrony and later developmental status. This study will expand our knowledge about the range of adaptation in term and preterm infants, identify differences in synchrony in early interaction, and relate them to later developmental outcomes. This evidence will provide an empirical basis for therapeutic nursing interventions with preterm infants.